#!/bin/sh
#
# The rkt HA resource agent creates and launches a container based off
# a supplied image. Containers managed by this agent are both created
# and removed upon the agent's start and stop actions.
#
# Copyright (c) 2017 Valentin Vidic <Valentin.Vidic@CARNet.hr>
#                    All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# Further, this software is distributed without any warranty that it is
# free of the rightful claim of any third person regarding infringement
# or the like.  Any license provided herein, whether implied or
# otherwise, applies only to this software file.  Patent licenses, if
# any, provided herein do not apply to combinations of this program with
# other software, or any other product whatsoever.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#

#######################################################################
# Initialization:

: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

#######################################################################

meta_data()
{
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="rkt" version="1.0">
<version>1.0</version>

<longdesc lang="en">
The rkt HA resource agent creates and launches a container
based off a supplied image. Containers managed by this agent
are both created and removed upon the agent's start and stop actions.
</longdesc>
<shortdesc lang="en">rkt container resource agent.</shortdesc>

<parameters>
<parameter name="image" required="1" unique="0">
<longdesc lang="en">
The image to base this container off of.
</longdesc>
<shortdesc lang="en">image</shortdesc>
<content type="string"/>
</parameter>

<parameter name="name" required="0" unique="0">
<longdesc lang="en">
The name to give the created container. By default this will
be that resource's instance name.
</longdesc>
<shortdesc lang="en">container name</shortdesc>
<content type="string"/>
</parameter>

<parameter name="allow_pull" unique="0">
<longdesc lang="en">
Allow the image to be pulled from the configured registry when
the image does not exist locally. NOTE, this can drastically increase
the time required to start the container if the image repository is
pulled over the network.
</longdesc>
<shortdesc lang="en">Allow pulling non-local images</shortdesc>
<content type="boolean"/>
</parameter>

<parameter name="run_opts" required="0" unique="0">
<longdesc lang="en">
Add options to be appended to the 'rkt run' command which is used
when creating the container during the start action. This option allows
users to do things such as setting a custom entry point and injecting
environment variables into the newly created container.

NOTE: Do not explicitly specify the --name argument in the run_opts. This
agent will set --name using either the resource's instance or the name
provided in the 'name' argument of this agent.

</longdesc>
<shortdesc lang="en">run options</shortdesc>
<content type="string"/>
</parameter>

<parameter name="run_cmd" required="0" unique="0">
<longdesc lang="en">
Specify a command to launch within the container once
it has initialized.
</longdesc>
<shortdesc lang="en">run command</shortdesc>
<content type="string"/>
</parameter>

<parameter name="mount_points" required="0" unique="0">
<longdesc lang="en">
A comma separated list of directories that the container is expecting to use.
The agent will ensure they exist by running 'mkdir -p'
</longdesc>
<shortdesc lang="en">Required mount points</shortdesc>
<content type="string"/>
</parameter>

<parameter name="monitor_cmd" required="0" unique="0">
<longdesc lang="en">
Specify the full path of a command to launch within the container to check
the health of the container. This command must return 0 to indicate that
the container is healthy. A non-zero return code will indicate that the
container has failed and should be recovered.

Note: Using this method for monitoring processes inside a container
is not recommended, as rkt tries to track processes running
inside the container and does not deal well with many short-lived
processes being spawned. Ensure that your container monitors its
own processes and terminates on fatal error rather than invoking
a command from the outside.
</longdesc>
<shortdesc lang="en">monitor command</shortdesc>
<content type="string"/>
</parameter>

<parameter name="force_kill" required="0" unique="0">
<longdesc lang="en">
Kill a container immediately rather than waiting for it to gracefully
shutdown
</longdesc>
<shortdesc lang="en">force kill</shortdesc>
<content type="boolean"/>
</parameter>

</parameters>

<actions>
<action name="start"        timeout="90s" />
<action name="stop"         timeout="90s" />
<action name="monitor"      timeout="30s" interval="30s" depth="0" />
<action name="meta-data"    timeout="5s" />
<action name="validate-all"   timeout="30s" />
</actions>
</resource-agent>
END
}

#######################################################################
REQUIRE_IMAGE_PULL=0

rkt_usage()
{
	cat <<END
usage: $0 {start|stop|monitor|validate-all|meta-data}

Expects to have a fully populated OCF RA-compliant environment set.
END
}


monitor_cmd_exec()
{
	local rc=$OCF_SUCCESS
	local out
	local uuid

	if [ -z "$OCF_RESKEY_monitor_cmd" ]; then
		return $rc
	fi

	uuid=$(container_uuid)
	out=$(rkt enter $uuid $OCF_RESKEY_monitor_cmd 2>&1)
	rc=$?

	if [ $rc -eq 127 ]; then
		ocf_log err "monitor cmd failed (rc=$rc), output: $out"
		ocf_exit_reason "monitor_cmd, ${OCF_RESKEY_monitor_cmd}, not found within container."
		# there is no recovering from this, exit immediately
		exit $OCF_ERR_ARGS
	elif [ $rc -ne 0 ]; then
		ocf_exit_reason "monitor cmd failed (rc=$rc), output: $out"
		rc=$OCF_ERR_GENERIC
	else
		ocf_log debug "monitor cmd passed: exit code = $rc"
	fi

	return $rc
}

container_exists()
{
	rkt list --no-legend | awk -v C=${CONTAINER} '$2 == C {exit 0} ENDFILE {exit 1}'
}

container_uuid()
{
	rkt list --no-legend --full | awk -v C=${CONTAINER} '$2 == C {print $1; exit}'
}

container_state()
{
	rkt list --no-legend | awk -v C=${CONTAINER} '$2 == C {print $4; exit}'
}

remove_container()
{
	local uuid

	container_exists
	if [ $? -ne 0 ]; then
		# don't attempt to remove a container that doesn't exist
		return 0
	fi

	uuid=$(container_uuid)
	ocf_log notice "Cleaning up inactive container, ${CONTAINER}."
	ocf_run rkt rm $uuid
}

rkt_simple_status()
{
	local val

	container_exists
	if [ $? -ne 0 ]; then
		return $OCF_NOT_RUNNING
	fi

	# retrieve the 'STATE' attribute for the container
	val=$(container_state)
	if [ "$val" = "running" ]; then
		# container exists and is running
		return $OCF_SUCCESS
	fi

	ocf_log debug "container ${CONTAINER} state is $val"
	return $OCF_NOT_RUNNING
}

rkt_monitor()
{
	local rc=0

	rkt_simple_status
	rc=$?

	if [ $rc -ne 0 ]; then
		return $rc
	fi

	monitor_cmd_exec
}

rkt_create_mounts() {
	oldIFS="$IFS"
	IFS=","
	for directory in $OCF_RESKEY_mount_points; do
		mkdir -p "$directory"
	done
	IFS="$oldIFS"
}

rkt_start()
{
	rkt_create_mounts
	local run_opts="--name=${CONTAINER}"

	# check to see if the container has already started
	rkt_simple_status
	if [ $? -eq $OCF_SUCCESS ]; then
		return $OCF_SUCCESS
	fi

	if [ -n "$OCF_RESKEY_run_cmd" ]; then
		run_opts="$run_opts --exec=$OCF_RESKEY_run_cmd"
	fi

	if [ -n "$OCF_RESKEY_run_opts" ]; then
		run_opts="$run_opts $OCF_RESKEY_run_opts"
	fi

	if [ $REQUIRE_IMAGE_PULL -eq 1 ]; then
		ocf_log notice "Beginning pull of image, ${OCF_RESKEY_image}"
		rkt fetch "${OCF_RESKEY_image}"
		if [ $? -ne 0 ]; then
			ocf_exit_reason "failed to pull image ${OCF_RESKEY_image}"
			return $OCF_ERR_GENERIC
		fi
	fi

	# make sure any previous container matching our container name is cleaned up first.
	# we already know at this point it wouldn't be running
	remove_container
	ocf_log info "Starting container, ${CONTAINER}."
	ocf_run systemd-run --slice=machine rkt run $OCF_RESKEY_image $run_opts

	if [ $? -ne 0 ]; then
		ocf_exit_reason "Failed to launch container"
		return $OCF_ERR_GENERIC
	fi

	while ! container_exists || [ "$(container_state)" = "preparing" ] ; do
		ocf_log debug "waiting for container to start"
		sleep 1
	done

	# wait for monitor to pass before declaring that the container is started
	while true; do
		rkt_simple_status
		if [ $? -ne $OCF_SUCCESS ]; then
			ocf_exit_reason "Newly created container exited after start"
			return $OCF_ERR_GENERIC
		fi

		monitor_cmd_exec
		if [ $? -eq $OCF_SUCCESS ]; then
			ocf_log notice "Container ${CONTAINER} started successfully as $(container_uuid)"
			return $OCF_SUCCESS
		fi

		ocf_exit_reason "waiting on monitor_cmd to pass after start"
		sleep 1
	done
}

rkt_stop()
{
	local timeout=60
	local uuid

	rkt_simple_status
	if [ $? -eq $OCF_NOT_RUNNING ]; then
		remove_container
		return $OCF_SUCCESS
	fi

	if [ -n "$OCF_RESKEY_CRM_meta_timeout" ]; then
		timeout=$(( $OCF_RESKEY_CRM_meta_timeout/1000 - 10 ))
		if [ $timeout -lt 10 ]; then
			timeout=10
		fi
	fi

	uuid=$(container_uuid)
	if ocf_is_true "$OCF_RESKEY_force_kill"; then
		ocf_log info "Killing container, ${CONTAINER}."
		ocf_run rkt stop --force $uuid
	else
		ocf_log info "Stopping container, ${CONTAINER}."
		ocf_run rkt stop $uuid
	fi

	if [ $? -ne 0 ]; then
		ocf_exit_reason "Failed to stop container, ${CONTAINER}, based on image, ${OCF_RESKEY_image}."
		return $OCF_ERR_GENERIC
	fi

	while [ $timeout -gt 0 ]; do
		rkt_simple_status
		if [ $? -eq $OCF_NOT_RUNNING ]; then
			break
		fi

		ocf_log debug "waiting for container to stop"
		timeout=$(( $timeout - 1 ))
		sleep 1
	done

	rkt_simple_status
	if [ $? -eq $OCF_SUCCESS ]; then
		ocf_exit_reason "Failed to stop container, ${CONTAINER}."
		return $OCF_ERR_GENERIC
	fi

	remove_container
	if [ $? -ne 0 ]; then
		ocf_exit_reason "Failed to remove stopped container, ${CONTAINER}, based on image, ${OCF_RESKEY_image}."
		return $OCF_ERR_GENERIC
	fi

	return $OCF_SUCCESS
}

image_exists()
{
	rkt image list --no-legend | awk -v I=${OCF_RESKEY_image} '$2 == I {exit 0} ENDFILE {exit 1}'
	if [ $? -eq 0 ]; then
		# image found
		return 0
	fi

	if ocf_is_true "$OCF_RESKEY_allow_pull"; then
		REQUIRE_IMAGE_PULL=1
		ocf_log notice "Image (${OCF_RESKEY_image}) does not exist locally but will be pulled during start"
		return 0
	fi

	# image not found.
	return 1
}

rkt_validate()
{
	check_binary rkt
	check_binary systemd-run

	if [ -z "$OCF_RESKEY_image" ]; then
		ocf_exit_reason "'image' option is required"
		exit $OCF_ERR_CONFIGURED
	fi

	if echo ${CONTAINER} | grep -q '[^a-z0-9-]'; then
		ocf_exit_reason "'name' must contain only lower case alphanumeric characters and -"
		exit $OCF_ERR_CONFIGURED
	fi

	image_exists
	if [ $? -ne 0 ]; then
		ocf_exit_reason "base image, ${OCF_RESKEY_image}, could not be found."
		exit $OCF_ERR_CONFIGURED
	fi

	return $OCF_SUCCESS
}

# TODO :
# When a user starts plural clones in a node in globally-unique, a user cannot appoint plural name parameters.

if ocf_is_true "$OCF_RESKEY_CRM_meta_globally_unique"; then
	if [ -n "$OCF_RESKEY_name" ]; then
		if [ -n "$OCF_RESKEY_CRM_meta_clone_node_max" ] && [ "$OCF_RESKEY_CRM_meta_clone_node_max" -ne 1 ]
		then
			ocf_exit_reason "Cannot make plural clones from the same name parameter."
			exit $OCF_ERR_CONFIGURED
		fi
		if [ -n "$OCF_RESKEY_CRM_meta_master_node_max" ] && [ "$OCF_RESKEY_CRM_meta_master_node_max" -ne 1 ]
		then
			ocf_exit_reason "Cannot make plural master from the same name parameter."
			exit $OCF_ERR_CONFIGURED
		fi
	fi
	: ${OCF_RESKEY_name=`echo ${OCF_RESOURCE_INSTANCE} | tr ':' '-'`}
else
	: ${OCF_RESKEY_name=${OCF_RESOURCE_INSTANCE}}
fi

CONTAINER=$OCF_RESKEY_name

case $__OCF_ACTION in
meta-data) meta_data
		exit $OCF_SUCCESS;;
start)
	rkt_validate
	rkt_start;;
stop)		rkt_stop;;
monitor)	rkt_monitor;;
validate-all)	rkt_validate;;
usage|help)	rkt_usage
		exit $OCF_SUCCESS
		;;
*)		rkt_usage
		exit $OCF_ERR_UNIMPLEMENTED
		;;
esac
rc=$?
ocf_log debug "${OCF_RESOURCE_INSTANCE} $__OCF_ACTION : $rc"
exit $rc
